Clinical Question

Can strep throat in children and adults be treated with five days of oral penicillin?

Bottom Line

Five days of 800-mg penicillin four times a day produced noninferior results to 10 days of 1,000-mg penicillin three times a day, with shorter symptom duration. This is not the first study to show similar benefits with a shorter duration of oral antibiotics. (Level of Evidence = 2b)

Synopsis

The investigators enrolled 317 adults and 105 children (six years and older) from 17 primary care centers in Sweden. Eligible patients had to have at least three Centor criteria and a positive rapid antigen test result for group A streptococcus. Using concealed allocation, patients were randomly assigned to receive either 800-mg penicillin four times a day for five days or 1,000-mg penicillin three times a day for 10 days. This was an open-label trial, meaning that patients and clinicians were aware of the treatment the patient received. The researchers who analyzed the data were masked to treatment until the results were assembled. Clinical cure, defined as complete recovery without major residual symptoms or clinical findings, was assessed five to seven days after the completion of treatment; that is, on day 10 to day 12 in the five-day treatment group and on day 15 to day 17 in the 10-day treatment group. This timing of assessment could possibly favor better results with longer treatment. In the per-protocol analysis (patients who completed treatment), cure rates at five to seven days post treatment were 89.6% in the five-day group and 93.3% in the 10-day group. Results were similar when using intention-to-treat analysis. Patients receiving the higher daily dose/shorter duration had quicker symptom resolution. Bacterial cure rates were higher with 10 days of treatment but there was no difference in complication rates or new episodes of tonsillitis at the three-month follow-up. Adverse events such as diarrhea, nausea, or vaginitis were more likely and lasted longer in the 10-day group. The study had a power of 85% to detect a greater than 10% difference between treatments if one existed.

Study design: Randomized controlled trial (single-blinded)

Funding source: Government

Allocation: Concealed

Setting: Outpatient (primary care)

Reference: Skoog Ståhlgren G, Tyrstrup M, Edlund C, et al. Penicillin V four times daily for five days versus three times daily for 10 days in patients with pharyngotonsillitis caused by group A streptococci: randomised controlled, open label, non-inferiority study. BMJ. 2019;367:l5337.

Editor's Note: Dr. Shaughnessy is an assistant medical editor for AFP.